Exploration of photocatalytic seawater splitting on Pt/GaP-C3N4 under simulated sunlight

Solar-driven photocatalytic seawater splitting for hydrogen is a promising process because of unlimited solar energy and seawater available. A novel Pt/GaP-C3N4 (PGC) heterogeneous photocatalyst was fabricated and used for photocatalytic artificial and natural seawater splitting under simulated sunlight illumination. The hybrid heterojunction structure of GaP-C3N4 promotes a Z-schematic electron migration and depresses the recombination rate of photogenerated electron-hole pairs in PGC photocatalyst. Under 4-hour simulated sunlight irradiation, the optimum composite 0.3PGC50 (0.3 wt% Pt-loaded and 50 wt% GaP-composited) exhibited high photoactivity performance with the hydrogen/oxygen evolution rate (HER/OER) of 46.5/23.4 µmol g−1 in deionized water, 65.5/34.3 µmol g−1 in the artificial seawater, and 53.9/24.9 µmol g−1 in the natural seawater splitting process. The apparent quantum yield of artificial seawater is near two times higher than that of pure water. The molar ratio of H2:O2 was near 2:1 matched whole water splitting, and the H2 yields were moderately decreased after 3 consecutive runs.